Datasheet

358
7593L–AVR–09/12
AT90USB64/128
Note: 1. Z0: should be zero for all SPM commands, byte select for the (E)LPM instruction.
See “Addressing the flash during self-programming” on page 350 for details about the use of Z-
pointer during Self-Programming.
Table 29-10.
Explanation of different variables used in Figure 29-4 on page 351 and the map-
ping to the Z-pointer.
Variable
Corresponding
Z-value Description
(1)
PCMSB 16
Most significant bit in the Program Counter. (The
Program Counter is 17 bits PC[16:0])
PAG EM SB 6
Most significant bit which is used to address the
words within one page (128 words in a page requires
seven bits PC [6:0]).
ZPCMSB Z17
Bit in Z-pointer that is mapped to PCMSB. Because
Z0 is not used, the ZPCMSB equals PCMSB + 1.
ZPAGEMSB Z7
Bit in Z-pointer that is mapped to PCMSB. Because
Z0 is not used, the ZPAGEMSB equals PAGEMSB +
1.
PCPAGE PC[16:7] Z17:Z8
Program Counter page address: Page select, for
Page Erase and Page Write
PCWORD PC[6:0] Z7:Z1
Program Counter word address: Word select, for
filling temporary buffer (must be zero during Page
Write operation)
PCMSB 15
Most significant bit in the program counter. (The
program counter is 16 bits PC[15:0])
PAG EM SB 6
Most significant bit which is used to address the
words within one page (128 words in a page requires
7 bits PC [6:0]).
ZPCMSB Z16
Bit in Z-register that is mapped to PCMSB. Because
Z0 is not used, the ZPCMSB equals PCMSB + 1.
ZPAGEMSB Z7
Bit in Z-register that is mapped to PAGEMSB.
Because Z0 is not used, the ZPAGEMSB equals
PAGEMSB + 1.
PCPAGE PC[15:7] Z16:Z7
Program counter page address: Page select, for
Page Erase and Page Write.
PCWORD PC[6:0] Z7:Z1
Program counter word address: Word select, for
filling temporary buffer (must be zero during PAGE
WRITE operation).